The cytotoxic activity of 13(E)-labd-13-ene-8α, 15-diol (1) was evaluated against tumor cell lines. A comparison of IC₅₀ values of this compound in cancer cell lines showed that their susceptibility to this compound decreased in the following order: P388>B16{F10>MDA-MB-231>A549>KB>SNU-C4 by the MTT method. 13(E}-Labd-13-ene-8α, 15-diol (1) was the most effective growth inhibitor of P388 murine leukaemia cell lines, producing approximately 8.3㎍/mL of IC₅₀ in the MTT method.